Oral administration of Euglena gracilis paramylon ameliorates chemotherapy-induced leukocytopenia and gut dysbiosis in mice

Euglena gracilis (EUG) is a food supplement rich in beta-glucans, which are stored in the form of granules called paramylon. We determined whether EUG improved chemotherapy-induced leukocytopenia and dysbiosis. Mice were orally administered EUG prior to gemcitabine treatment. Analyses of the blood cell count, leukocyte population in the spleen, granulocyte/macrophage–colony-stimulating factor (GM–CSF) production by splenocytes, and fecal microbiome were conducted. The recovery of total leukocytes, neutrophils, and monocytes was accelerated after a single gemcitabine treatment. A more rapid lymphocyte recovery rate was observed after four gemcitabine treatments. No difference was observed in the percentage of T, B, or myeloid cells or in the expression of Dectin-1 in the spleens of the gemcitabine and EUG/gemcitabine groups. The EUG/gemcitabine group showed an enhanced GM–CSF production by lipopolysaccharides-stimulated splenocytes. Next-generation sequencing revealed that gemcitabine-induced dysbiosis was alleviated. This study demonstrated that EUG-derived beta-glucans could act as a biological response modifier as well as prebiotics for ameliorating chemotherapy-induced adverse effects.